[Crustacea • 2026] Pilumnus guadeloupensis • A New Species of Pilumnus Leach, 1816 (Decapoda: Brachyura) from Guadeloupe, Lesser Antilles

 

Pilumnus guadeloupensis 

Magalhães, Oliveira-Rogeri, Felder & Mantelatto, 2026

DOI: doi.org/10.5252/zoosystema2026v48a16

 Abstract  

Pilumnus Leach, 1861 is a speciose cosmopolitan genus of marine crabs typical from rocky and coral coastal environments and known to occur in tropical and temperate oceans and seas worldwide, including the waters of western Atlantic and Caribbean Sea surrounding the Lesser Antilles, a recognized hotspot of biodiversity in Caribbean. Despite recent sampling efforts, this region remains underexplored, limiting understanding of its marine fauna. To address this gap, several field expeditions have been carried out, including KARUBENTHOS 2012. This expedition extensively collected specimens of various taxonomic groups, expanding documentation of biodiversity in the Lesser Antilles. Among collections, a unique specimen of Pilumnus was recognized and analyzed through morphological and molecular approaches. Genetic analyses of this specimen, a component of molecular phylogenetic studies previously conducted by our team, confirmed its divergence from previously described species. Herein, we performed a thorough morphological examination analyzing most of the taxonomic informative characters used in species descriptions of representatives of Pilumnus. Based on the presently accessed morphological features and previously detected molecular divergence, a new species, Pilumnus guadeloupensis n. sp., is described. This species can be distinguished from others from the genus mainly by the ornamentation and tuberculation patterns of pereopods, number of anterolateral prominences and shape of the carapace. Detailed morphological comparisons with congeners, alongside a comprehensive review of the literature, are provided.

KEYWORDS: Caribbean, KARUBENTHOS 2012, morphology, Pilumnidae, new species, 

Habitus of alcohol-preserved holotype of Pilumnus guadeloupensis n. sp., male (CW = 6.44 mm),  MNHN-IU-2013-16321:
A, dorsal; B, ventral.

 Scale bar: 2 mm.

Holotype of Pilumnus guadeloupensis n. sp., male (CW = 6.44 mm),  MNHN-IU-2013-16321:
A, entire specimen on dorsal view; B, left third maxilliped, external; C, outer surface of major chela; D, left first gonopod, mesial; E, pleon and telson.

 Scale bars (mm): A, 3 mm; B, 0.7 mm; C, 2.5 mm; D, 0.2 mm; E, 1.5 mm.

Alcohol-preserved holotype of Pilumnus guadeloupensis n. sp., male (CW = 6.44 mm),  MNHN-IU-2013-16321:
A, habitus, frontal; B, carapace front, dorsal; C, left anterolateral carapace margin, dorsal; D, left suborbital and pterygostomial carapace regions, ventral; E, left third maxilliped, external; F, left (major) cheliped, dorsal; G, right (minor) chela, external; H, left (major) chela, external; I, right pereopods 4 and 5, meri, carpi, and propodi, dorsal; J, anterior sternites and pereopod coxae, ventral; K, sternopleonal cavity with pleonal lock button; L, left first gonopod, mesial. Not to scale.

Phylum ARTHROPODA Latreille, 1829

Class MALACOSTRACA Latreille, 1802

Order DECAPODA Latreille, 1802

Infraorder BRACHYURA Latreille, 1802

Family PILUMNIDAE Samouelle, 1819

Genus Pilumnus Leach, 1816

Pilumnus guadeloupensis n. sp.

 

Diagnosis. — Carapace anterodorsally with short pubescence; frontal, protogastric, and hepatic regions of dorsal surface with strong tubercules; supraorbital margins strongly toothed; anterolateral margin with four teeth, anteriormost of which formed by outer orbital tooth. Major chela palm with outer surface nearly smooth and glabrous. Ambulatory pereopods with merus dorsal margin mostly smooth, single subdistal denticle on dorsal margin of meri of pereopods 2-4; carpi and propodi with prominent spiniform tubercles.

Etymology. — The specific epithet guadeloupensis refers to Guadeloupe, the type locality of the species, and it is used here as an adjective.

 

Tatiana Magalhães, Lucas Oliveira-Rogeri, Darryl L. Felder and Fernando L. Mantelatto. 2026. A New Species of Pilumnus Leach, 1816 (Decapoda, Brachyura) from Guadeloupe, Lesser Antilles, with morphological comparisons to regional congeners. Zoosystema. 48 (16), 389-399. DOI: doi.org/10.5252/zoosystema2026v48a16 (3 July 2026)

Une nouvelle espèce de Pilumnus Leach, 1816 (Decapoda, Brachyura) de Guadeloupe, Petites Antilles, et comparaisons morphologiques avec les espèces régionales apparentées.

Pilumnus Leach, 1861 est un genre cosmopolite de crabes marins, typique des environnements côtiers rocheux et coralliens. Ces animaux sont présents dans les océans et mers tropicaux et tempérés du monde entier, notamment dans les eaux de l'Atlantique ouest et la mer des Caraïbes, y compris dans les eaux entourant les Petites Antilles, un point chaud de biodiversité en région caraïbe. Malgré de récents efforts d'échantillonnage, cette région reste sous-explorée, ce qui limite la connaissance de sa faune marine. Pour combler cette lacune, plusieurs expéditions de terrain ont été menées, dont KARUBENTHOS 2012. Cette expédition a permis de collecter de nombreux spécimens de divers groupes taxonomiques, enrichissant ainsi nos connaissances sur la biodiversité des Petites Antilles. Parmi les spécimens collectés, un spécimen unique de Pilumnus a été identifié et analysé par des approches morphologiques et moléculaires. Les analyses génétiques de ce spécimen, réalisées dans le cadre d'études de phylogénie moléculaire précédemment menées par notre équipe, ont confirmé sa divergence avec les espèces précédemment décrites. Un examen morphologique approfondi analysant la plupart des caractères taxonomiques informatifs utilisés dans les descriptions des espèces de Pilumnus a été réalisé. Sur la base des caractéristiques morphologiques décrites dans cette étude et des divergences moléculaires précédemment détectées, une nouvelle espèce, Pilumnus guadeloupensis n. sp., est décrite. Cette espèce se distingue des autres espèces du genre principalement par l'ornementation et les tubercules des péréiopodes, le nombre de proéminences antérolatérales et la forme de la carapace. Des comparaisons morphologiques détaillées avec ses congénères, ainsi qu'une revue exhaustive de la littérature, sont fournies.

Caraïbes, KARUBENTHOS 2012, morphologie, Pilumnidae, espèce nouvelle

[Crustacea • 2026] Lemurophusa empusa & Balssiathelphusa inopinata • Revision of the Southeast Asian freshwater crab Genus Balssiathelphusa Bott, 1969 (Decapoda: Brachyura: Gecarcinucidae)

Lemurophusa empusa

Ng & Guinot, 2026

DOI: doi.org/10.5252/zoosystema2026v48a18 

 Abstract 

The systematics of the gecarcinucid genus Balssiathelphusa Bott, 1969 is revised. Balssiathelphusa has an atypical distribution pattern for a freshwater crab genus, with the four known species recorded from Sumatra, Borneo and Natuna Islands in the South China Sea. The type species, Para-Perithelphusa sucki Balss, 1937 [sic, see infra], is redescribed and figured, and the genus is redefined to include B. sucki, B. cursor Ng, 1986, from East Kalimantan in Indonesian Borneo, and a new species, B. inopinata n. sp., also from East Kalimantan. The type locality of B. sucki was reported as southeastern Sumatra, but the available evidence suggests the holotype was actually collected from South Kalimantan in Borneo. Balssiathelphusa natunaensis Bott, 1970, from Natuna Island, is transferred to a new monotypic genus, Natunusa n. gen., while B. phasma Ng & Guinot, 2014, collected from a cave in East Kalimantan, is referred to a separate genus, Lemurophusa n. gen. A new species, L. empusa n. gen., n. sp., is also described from another karst system in East Kalimantan, whereas a juvenile female from a nearby cave in East Kalimantan is treated as Lemurophusa sp. Particular attention was paid to the thoracic sternum and its sutures, to the median bridges between the sternites, as well to the median line, characters often overlooked but that are particularly useful in this group of small gecarcinucid crabs.

KEYWORDS: Borneo, Sumatra, Natuna Islands, Kalimantan, Gecarcinucoidea, freshwater crab, cave crab, new genera, new species 

 

Superfamily Gecarcinucoidea Rathbun, 1904

Family Gecarcinucidae Rathbun, 1904

Genus Balssiathelphusa Bott, 1969

Balssiathelphusa Bott, 1969: 364; 1970: 98. — Ng 1986a: 207.

Included species. — Balssiathelphusa sucki (Balss, 1937), B. cursor Ng, 1986; B. inopinata n. sp.

Balssiathelphusa inopinata n. sp.

Etymology. — The name is derived from the Latin “inopinatus” for “unexpected” as it had been previously believed that Nobili's (1903) record was Balssiathelphusa cursor and not a new species.

Natunusa natunaensis (Bott, 1970) n. comb., ♂ 12.9 × 11.3 mm (ZRC 2021.0831), Natuna Island:
A, overall dorsal habitus; B, dorsal view of carapace; C, frontal view of cephalothorax; D, frontal median triangle, antennules, antennae and epistome; E, buccal cavity, anterior thoracic sternum, telson and pleonal somites 5 and 6; F, posterior thoracic sternum and pleonal somites 1-4; G, sternopleonal cavity.

Genus Natunusa n. gen.

 

Type species. — Balssiathelphusa natunaensis Bott, 1970, 

by original designation and monotypy.

Diagnosis. — Carapace quadrate, just wider than long; carapace not high, height to width ratio 0.4; epigastric cristae rugose, low but visible, not cristate; postorbital cristae low, rugose, discernible, not cristate; frontal margin divided into two low lobes; frontal median triangle distinct, with dorsal crista straight; external orbital tooth with outer margin 3.0-4.0 times length of inner margin; epibranchial tooth small, low, separated from margin by small notch; rest of anterolateral margins gently convex; posterolateral ...

Etymology. — The name is derived from the name of the type locality, Natuna Island, in arbitrary combination with -phusa, a common suffix for gecarcinucid genera. The gender of the name is feminine.

Included species. — Natunusa natunaensis (Bott, 1970) n. comb.

Lemurophusa empusa n. gen., n. sp.:
 A, C, holotype, ♀ 24.2 × 18.5 mm (MZB Cru), Kalimantan;
B, D, paratype ♀ 22.2 × 17.2 mm (MZB Cru), Kalimantan.
A, B, overall dorsal habitus; C, D, dorsal view of carapace.

Genus Lemurophusa n. gen. 

Type species. — Balssiathelphusa phasma Ng & Guinot, 2014, 

by present designation.

Included species. — Lemurophusa phasma (Ng & Guinot, 2014) n. comb.; Lemurophusa empusa n. sp.

Diagnosis. — Carapace transversely ovate, wider than long, carapace not high, height to width ratio 0.4; epigastric cristae low, rugose but visible; postorbital cristae low, rugose, just discernible, not cristate; frontal margin divided into two low lobes; frontal median triangle distinct, with dorsal crista medially bent, fused with lateral cristae; external orbital tooth distinct, with outer margin about twice length of inner margin; epibranchial tooth small, low, separated from margin by notch; rest of anterolateral margins ...

Etymology. — The name is derived from the Latin word “lēmurēs” for “spirits of the dead”; in arbitrary combination with -phusa, a common suffix for gecarcinucid genera. This alludes to the cave habitat of the species. The gender of the name is feminine.

Lemurophusa empusa n. sp.

Etymology. — The species is named after Empusa, a demigoddess of Greek mythology. The name is used as a noun in apposition.

Peter K. L. Ng and Danièle Guinot. 2026. Revision of the Southeast Asian freshwater crab Genus Balssiathelphusa Bott, 1969 (Crustacea, Decapoda, Brachyura, Gecarcinucidae). Zoosystema. 48 (18); 557-587. DOI: doi.org/10.5252/zoosystema2026v48a18 (13 July 2026)

Révision du genre de crabes d'eau douce d'Asie du Sud-Est Balssiathelphusa Bott, 1969 (Crustacea, Decapoda, Brachyura, Gecarcinucidae).

Bornéo, Sumatra, îles Natuna, Kalimantan, Gecarcinucoidea, crabe d'eau douce, crabe cavernicole, genres nouveaux, espèces nouvelles

[Crustacea • 2026] Cambarus emegi • A New Stream-dwelling Species of Cambarus (Decapoda: Cambaridae) from Virginia and Pennsylvania (USA) with Notes on its Distribution, Ecology, and Conservation Status

 

Cambarus emegi 

Lieb, Williams, Foltz & Loughman, 2026 

 

DOI: doi.org/10.11646/zootaxa.5857.2.5 

  facebook.com/WLUCrayfish

Abstract

A new species of crayfish, Cambarus emegi sp. nov., is described from the upper James and Roanoke River basins in Virginia and the lower Delaware River basin in Pennsylvania, where it occurs in streams and small rivers. The species was formerly part of the Cambarus acuminatus species complex (Cambarus species C complex), a long-standing taxonomic enigma that is widely distributed across the Atlantic slope drainages of eastern North America. Cambarus emegi sp. nov. can be distinguished from Cambarus acuminatus due to the absence of a well-defined subpalmar tubercle, greater number of punctations across its areola, and differences in the mesial process of the form I male gonopod. Coloration and pattern in life differ between the two species. Additionally, the distributions of C. emegi sp. nov. and C. acuminatus are separated by hundreds of kilometers. The ranges of two other undescribed members of the Cambarus species C complex border that of C. emegi sp. nov. in Virginia. These species do not appear to overlap geographically; C. emegi sp. nov. is confined to the Ridge and Valley physiographic province, whereas the two undescribed species are found in the Blue Ridge and northern inner Piedmont regions. Cambarus emegi sp. nov. is morphologically similar but visually and genetically different from the undescribed species directly to the south in the upper Roanoke River system. Cambarus emegi sp. nov. is both visually and morphologically similar but genetically distinct from the undescribed species immediately downstream in the James River basin. Cambarus emegi sp. nov. is threatened by several potentially interacting factors including invasive crayfishes, narrow range, and urban and agricultural development. Alarmingly, the species is being rapidly replaced by invasive Faxonius species across a substantial part of its range. This paper represents an important step in providing the information needed to conserve and manage Cambarus emegi sp. nov.

Crustacea, Cambarus species C., Cambarus acuminatus, new species, Ridge and Valley, Northern Piedmont, Delaware, James, Roanoke, invasive crayfish

 Cambarus emegi sp. nov., color in life: (a) holotype, NCSM 95987; (b) allotype, NCSM 95988.

Life color and color pattern of adult  Cambarus emegi sp. nov.:
 (a) dorsal view; (b) oblique lateral view (photo credit Zackary A. Graham).

 Life color and color pattern of juvenile  Cambarus emegi sp. nov. 

Cambarus emegi sp. nov. 

Diagnosis.—Body and eyes pigmented. Rostrum weakly to moderately excavated and ventrally deflected anteriorly; rostral margins subparallel, pronounced and entire through acumen, and more thickened posteriorly than anteriorly; acumen acuminate with prominent dorsally deflected spiniform tubercle at terminus. Areola 2.2–3.6 (¯x=2.7, n=42, s=0.4) times as long as wide, with 6–10 (¯x=8.5, n=42, s= 0.7) punctations across narrowest point. Lateral portion of branchiostegal region of carapace heavily punctate; hepatic regions also punctate with welldeveloped tubercles. Strong cervical spines present; branchiostegal spine prominent; postorbital ridge terminating anteriorly in spiniform tubercle or spine. Weak to acute suborbital angle typically present, rarely absent; suborbital angle terminating anteriorly in spiniform tubercle or spine. Antennal basipodite spines prominent; ischiopodite spines present but not prominent.

Etymology.—Derived from the Turkish work “emeği” meaning “labor of” or “hard work of”, which seems appropriate given this project required many years and the collection of thousands of specimens from South Carolina to Pennsylvania. Additionally, the name honors Emily (Em) and Megan (Meg) Lieb, the senior author’s two daughters, who happily accompanied him on many crayfish sampling trips as children and later helped him collect C. emegi sp. nov. from sites in its Pennsylvania range. 

Common name.—We propose Enigma Crayfish as the common name.

David A. LIEB, Bronwyn W. WILLIAMS, David A. FOLTZ II and Zachary J. LOUGHMAN. 2026. Description of A New Stream-dwelling Species of Cambarus (Decapoda: Cambaridae) from Virginia and Pennsylvania (USA) with Notes on its Distribution, Ecology, and Conservation Status.  Zootaxa. 5857(2); 299-316. DOI: doi.org/10.11646/zootaxa.5857.2.5 [2026-07-29]

 facebook.com/WLUCrayfish/posts/1731022025695189 

[Crustacea • 2026] Pachycheles ravichandrani • A New Species of Porcelain Crab (Decapoda: Porcellanidae) from Lakshadweep, India

 

Pachycheles ravichandrani 

Sureandiran, Radhakrishnan, S. Kumar & T. T. A. Kumar, 2026

DOI: doi.org/10.11646/zootaxa.5849.2.6 

 Researchgate.net/publication/409222030 

Abstract

A new species of porcelain crab, Pachycheles ravichandrani sp. nov. is described from specimens collected at Agatti Island, Lakshadweep, India. Pachycheles ravichandrani sp. nov. shares similar morphology with P. garciaensis (Ward 1942) and P. setiferous Yang, 1996 in the following characters: carapace with trilobed front, cheliped without setae, 5-plated telson and presence of a pair of pleopods in males. The new species, however, is differentiated by the presence of setae along lateral ridges and posterior margin of carapace, minor cheliped with distinct gap between fingers and cutting edge of minor cheliped truncate. To validate the taxonomic status of the new species, molecular analysis, using COI and 16S rRNA genes were carried out. Phylogenetic reconstruction consistently showed P. ravichandrani sp. nov. as a distinct, well-supported lineage separate from all congeners. Genetic divergence within the genus Pachycheles ranged from 12.6–21.7% (COI) and 4.0–13.7% (16S rRNA).

Crustacea, Crab, Integrative taxonomy, Indian Ocean, Lakshadweep reefs

Pachycheles ravichandrani sp. nov. in live condition, collected from Agatti Island, Lakshadweep. Specimen not preserved. Scale bar: 1 mm.

Pachycheles ravichandrani sp. nov., holotype male, PORPRAV/NBFGR, CW 3.69 mm.

 A, carapace, dorsal view; B, frontal lobe, frontal view; C, antennular peduncle, dorsal view; D, antennule basal segment, dorsal view; E, maxilliped 3, ventral view; F, thoracic sternite, ventral view; G, pleopod, dorsal view. 

Scale bars: A, B, F = 1 mm; C–E, G = 0.5 mm.

 A, major cheliped, dorsal view; B, fingers of major cheliped, closer view; C, minor cheliped, dorsal view (paratype male, PORPRAV/NBFGR.1); D, fingers of minor cheliped, closer view (paratype male); E, P2, lateral view; F, P3, lateral view; G, P4, lateral view; H, P5, lateral view. 

Scale bars: A–D = 1 mm; E–H = 0.5 mm.

Pachycheles ravichandrani sp. nov. 

BALAMURUGAN SUREANDIRAN, DIVYA PREMA RADHAKRISHNAN, SENDHIL KUMAR and THIPRAMALAI THANGAPPAN AJITH KUMAR. 2026. Pachycheles ravichandrani, A New Species of Porcelain Crab from Lakshadweep, India (Crustacea: Decapoda: Porcellanidae).  Zootaxa. 5849(2); 227-238. DOI: doi.org/10.11646/zootaxa.5849.2.6 [2026-07-13]

 Researchgate.net/publication/409222030_Pachycheles_ravichandrani_a_new_species_of_porcelain_crab_from_Lakshadweep_India

[Crustacea • 2025] Cambarus ocoeensis • A New Species of Crayfish (Decapoda: Cambaridae) from the Ocoee River Basin of Tennessee, USA

 

Cambarus ocoeensis 

 Thoma & Williams, 2025 

DOI: doi.org/10.11646/zootaxa.5618.1.7  

  Researchgate.net/publication/390392403 

  facebook.com/RogerFThoma

Abstract

Cambarus ocoeensis sp. nov. is described from the Ocoee River Gorge area of Tennessee. The species is morphologically most similar to Cambarus hiwasseensis Hobbs, 1981, but differs from C. hiwasseensis in the following ways: first pereopod chelae in general less sculpted, usually with one row of palmer tubercles, if second row present very weakly developed and consisting of six or fewer tubercles, lateral margin not costate, lateral impression weak at most but usually absent; areola length 2.5–4.1 times greater than width, having 5–8 punctations in narrowest part; size at maturity smaller with MI ranging from 21.8 to 30.9 mm total carapace length (24.6–40.0 mm in C. hiwasseensis); and antennal scale broadest at midpoint. It can be distinguished from other morphologically similar species—those with acuminate rostra—from the Hiwassee River basin of northern Georgia, southeast Tennessee, and western North Carolina area in lacking lateral rostral spines/tubercles and cervical spines. Cambarus ocoeensis sp. nov. is genetically most closely related to an undescribed member of the Cambarus bartonii (Fabricius, 1798) species complex.

 

Crustacea, C. hiwasseensis, C. bartonii, C. howardi, Hiwassee River basin, species complex

Type material of Cambarus ocoeensis sp. nov.:
 A–C, E, G–I, holotype MI (OSUMC #10897); F, allotypic paratypefemale (OSUMC #10898); D, morphotypic paratype MII (OSUMC #10899).
A–carapace, dorsal view; B–gonopod, lateralview; C–gonopod, mesial view; D–gonopod, lateral view; E–antennal scale, dorsal view; F–annulus ventralis; G–pereopods3–5, right side ventral views; H–epistome; I–right chela, dorsal view. 

Color image of Cambarus ocoeensis sp. nov., holotype (OSUMC #10897).

Image captured in lab under artificial light.

Cambarus ocoeensis sp. nov. 

Roger F. THOMA and Bronwyn W. WILLIAMS. 2025. Cambarus ocoeensis, A New Species of Crayfish (Decapoda: Cambaridae) from the Ocoee River Basin of Tennessee, USA.  Zootaxa. 5618(1); 106-118. DOI: doi.org/10.11646/zootaxa.5618.1.7 [2025-04-01] 

 Researchgate.net/publication/390392403_Cambarus_ocoeensis_a_new_species_of_crayfish_from_the_Ocoee_River_Basin_of_Tennessee_USA

  facebook.com/RogerFThoma/posts/10228373600190065

[Crustacea • 2026] Geosesarma penrissen • A New Species of Vampire Crab of the Genus Geosesarma De Man, 1892 (Brachyura: Sesarmidae) from A montane forest in southwestern Sarawak, Malaysian Borneo

 

Geosesarma penrissen

Grinang, P. Y. C. Ng & P. K. L. Ng, 2026 

 

The Raffles Bulletin of Zoology. 74; 

Abstract 

 A new species of semiterrestrial crab, Geosesarma penrissen, new species, is described herein from Mount Penrissen in southwestern Sarawak, Malaysia. It represents the third species of Geosesarma known from the montane forests of Borneo, the other two being G. larsi Ng & Grinang, 2018 from Mount Ampungan in Serian, Sarawak, and G. aurantium Ng, 1995 from Mount Silam in Sabah. Diagnostic characters distinguishing G. penrissen, new species, from its congeners are provided, together with ecological notes on its highland habitat. 

Key words. freshwater crab, semiterrestrial, taxonomy, lowland forest, comparative morphology

Geosesarma penrissen, new species, live colouration.
A–C, holotype male (10.6 × 10.2 mm) (ZRC 2024.0567); D, paratype male (10.7 × 10.5 mm) (ZRC 2024.0171); E, adult male, on shrub, Batu Panggah trail, photographed 2311 hrs; 6 July 2023 (not collected); F, subadult, on shrub, Batu Panggah trail, photographed 2118 hrs, 6 July 2023 (not collected).

All specimens from Sarawak. E, F, photographed by Chien Lee.

 Geosesarma penrissen, new species

Diagnosis. Carapace almost square, width-to-length ratio 1.01–1.07, lateral margins gently sinuous, subparallel (Figs. 1A, D, 2A–D, 5A, C, F, 6A, D); dorsal surface with welldefined regions, anterior regions covered with small, rounded or flattened, squamate granules (Figs. 1A, C, E, F, 2A–D, 5A, C, E, 6A, D); front deflexed, with 2 broad subtruncate lobes, separated by shallow median concavity; postfrontal, protogastric lobe prominent, sharp-edged (Figs. 1A, C, D, 2A–D, 3A, 6C, F); external orbital tooth acutely triangular, outer margins curving anteriorly, tooth directed obliquely and laterally, clearly extending beyond lateral margin of carapace (Figs. 2A–D, 5A, C, E, 6A, D). Merus of third maxilliped ...

JONGKAR GRINANG, PAUL Y. C. NG and PETER K. L. NG. 2026. A New Species of Vampire Crab of the Genus Geosesarma De Man, 1892 (Crustacea: Brachyura: Sesarmidae) from A montane forest in southwestern Sarawak, Malaysian Borneo. The Raffles Bulletin of Zoology. 74; 457–464.

[Crustacea • 2025] Umalia modesta • A New Species of Frog Crab Genus Umalia Guinot, 1993 (Brachyura: Raninidae) from the South China Sea, with A Key to Species in the Genus

 

Umalia modesta

Ng, 2025

DOI: doi.org/10.18353/crustacea.54.0_53

Abstract 

A new species of raninid frog crab, Umalia modesta n. sp., is described from the northern part of the South China Sea, near Tungsha Islands. The species is morphologically most similar to U. chinensis (Chen & Sun, 2002) (from southern China) and U. tenuiocellus (Davie & Short, 1989) (from Australia) but can easily be distinguished from them by its carapace form, well developed cornea, and structures of the rostrum, thoracic sternum, third maxilliped and ambulatory legs.  

Key words: Tungsha Islands, Taiwan, Raninoidea, new species, comparative taxonomy, genus key

Umalia modesta n. sp., holotype female (11.0×14.0 mm) (ZRC 2024.0500), South China Sea.
A, overall dorsal view; B, frontal half of carapace (dorsal view); C, frontal view of cephalothorax; D, left anterolateral view of cephalothorax; E, third maxillipeds.

Umalia modesta n. sp., male, station CP4115,
southwest of Tungsha Island, South China Sea [specimen not examined]

[Photograph: T.-Y. Chan].

Superfamily Raninoidea De Haan, 1839 

Family Raninidae De Haan, 1839 

Subfamily Notopodinae Serène & Umali, 1972 

Umalia Guinot, 1993

Umalia modesta, new species 

Diagnosis: Carapace shape trapezoidal, anterior part much wider than posterior part, lateral margins almost straight, subparallel; carapace width more than 0.7 total length; fronto-orbital distance less than half width of carapace; anterior ...

Etymology: From the Latin “modesta” for unassuming, alluding to the simple characters of the species

Peter K. L. Ng. 2025. On A New Species of Frog Crab, Umalia modesta n. sp. (Brachyura: Raninidae) from the South China Sea, with A Key to Species in the Genus. Crustacean Research. 54; 53-61. DOI: doi.org/10.18353/crustacea.54.0_53 [September 27, 2025]

[Crustacea • 2024] Geothelphusa amakusa & G. mutsu • The Identity of the Japanese Freshwater Crab, Geothelphusa dehaani (White, 1847) (Decapoda: Brachyura: Potamidae), with Descriptions of Two New Species from Japan

Geothelphusa mutsu

   Geothelphusa amakusa 

  

Naruse & Ng, 2024

DOI: 10.18353/crustacea.53.0_53 

Abstract 

This study designates a lectotype for and redescribes Thelphusa dehaani White, 1847, a Japanese primary freshwater crab species belonging to the potamid genus Geothelphusa Stimpson, 1858. Geothelphusa dehaani was described based on material exported to the Netherlands by von Siebold. Although the provenance of all his specimens is uncertain (they may be from several locations), our morphological comparison of the lectotype with fresh specimens led us to ascertain that it was almost certainly collected from Nagasaki, where von Siebold stayed. Two new Geothelphusa species are also described from Amakusa Islands and Aomori Prefecture.

Keywords: Taxonomy, primary freshwater crab, Potamoidea, von Siebold

Coloration of Geothelphusa amakusa n. sp. 
A, holotype, RUMF-ZC-8152, male, 30.3×22.5 mm; B, RUMF-ZC-8153, female, 28.8×22.7 mm;
C, D, 20161020; E, 20161020; F, ZRC 2017.0975, male, 18.9×14.8 mm.

Geothelphusa amakusa n. sp. 

Etymology The species is named after the type locality, Amakusa Island. The name is used as a noun in apposition.

Coloration of Geothelphusa mutsu n. sp.
 A, male, ZRC 2018.0716, 19.3×15.1 mm; B, female, ZRC 2018.0716, 24.1× 18.4 mm; C, D, male, ZRC 2018.0716, 20.4 × 15.3 mm.

Geothelphusa mutsu n. sp.

Etymology The species is named after “Mutsunokuni”, a previous estate name of the type locality (Aomori Prefecture) and also a historical province name for a larger area of northern Honshu Island. The name is used as a noun in apposition.

Tohru Naruse and Peter K. L. Ng. 2024. The Identity of the Japanese Freshwater Crab, Geothelphusa dehaani (White, 1847) (Decapoda: Brachyura: Potamidae), with Descriptions of Two New Species from Japan. Crustacean Research. 53; 53-71. DOI: doi.org/10.18353/crustacea.53.0_53

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[Crustacea • 2026] Frodromia elegans, F. granulosa, ... • Revision of Frodromia McLay, 1993 (Brachyura: Dromiidae) and the Status of Frodromiinae Števčić, 2005

A, Frodromia atypica (Sakai, 1936),; B, F. reticulata (Sakai, 1974);
C, F. elegans, new species, holotype male, Taiwan; D, F. granulosa, new species, holotype male, Vanuatu;
 E, F, F. iners, new species, holotype male, Philippines. 

Ng, 2026 

RAFFLES BULLETIN OF ZOOLOGY. 74: 

Photographs: C, T.-Y. Chan; D, J.C.E. Mendoza; E, F, P.K.L. Ng.

Abstract

 The taxonomy of the West Pacific dromiid genus, Frodromia McLay, 1993, is revised using a suite of characters pertaining to the carapace form and armature, proportions of the ambulatory dactylus, and structures of the pereopods, thoracic sternum, male pleon, and gonopods. The identity of the poorly known type species, F. atypica (Sakai, 1936), is clarified and the species is rediagnosed and illustrated based on the single non-type dried specimen available. Frodromia reticulata (Sakai, 1974) is also rediagnosed on the basis of a series of Japanese specimens. The material identified as F. atypica by McLay (1993) from New Caledonia and the Indonesian Moluccas is here shown to belong to two new species, F. granulosa and F. caileani, respectively; with F. granulosa also reported from Vanuatu. Two other new species, F. elegans and F. iners, are described from the South China Sea and the Philippines, respectively. As a result, Frodromia is hereby classified in the subfamily Frodromiinae Števčić, 2005, which was originally established as a tribe in Sphaerodromiinae Guinot & Tavares, 2003, and which is here redefined and rediagnosed.

Key words. sponge crab, Dromioidea, systematics, subfamily definition, new species, key to taxa, Indo-West Pacific

Colour in life. A, Frodromia atypica (Sakai, 1936), after Sakai (1936: pl. 2 fig. 1); B, F. reticulata (Sakai, 1974), after Sakai (1976: pl. 5 fig. 1);
C, F. elegans, new species, holotype male (6.6 × 7.5 mm) (ZRC 2024.0144), Taiwan; D, F. granulosa, new species, holotype male (6.5 × 7.1 mm) (ZRC 2024.0517), Vanuatu;
E, F, F. iners, new species, holotype male (6.3 × 7.0 mm) (ZRC 2024.0518), Philippines [partly covered with sand particles and debris].

Photographs: C, T.-Y. Chan; D, J.C.E. Mendoza; E, F, P.K.L. Ng.

Frodromia granulosa 

F. caileani 

F. elegans 

 F. iners

PETER K. L. NG. 2026. Revision of Frodromia McLay, 1993 (Crustacea: Brachyura: Dromiidae) and the Status of Frodromiinae Števčić, 2005. RAFFLES BULLETIN OF ZOOLOGY. 74: 332–358. DOI: 10.26107/RBZ-2026-0023  [4 May 2026]

[Crustacea • 2026] Nephropsis perexigua • A New Species of Nephropsis Wood-Mason, 1872 (Decapoda: Astacidea: Nephropidae) [the World’s Smallest Clawed Lobster]

Nephropsis perexigua

Chan & Chang, 2026

 DOI: doi.org/10.1093/jcbiol/ruag015 

Abstract

Several small specimens of a clawed lobster recently collected off the island of Guadeloupe in the West Indies and originally reported as Nephropsis aculeata Smith, 1881 are found to represent a species new to science. The new species, N. perexigua sp. nov., can be readily separated from N. aculeata by the absence of a dorsal median carina in the abdomen. Nephropsis perexigua sp. nov. actually closely resembles N. pygmaea Chang, Chan & Kumar, 2020 from the West Pacific, but differs in the abdomen being smooth. The shape of the posteromesial plate on the coxa of the pereiopod III is also distinctly different among males of N. perexiguasp. nov., N. aculeata, and N. pygmaea. The large sequence divergence in the barcoding gene COI supports the distinct specific status of the new species. With the carapace length of the largest specimen being 12.1 mm and the smallest ovigerous female only 10.0 mm, N. perexiguasp. nov. is the world’s smallest clawed lobster so far known. An updated key to the species of Nephropsis Wood-Mason, 1872 is provided.

Nephropsis perexigua sp. nov.

Tin-Yam Chan and Su-Ching Chang. 2026. Description of the World’s Smallest Clawed Lobster, A New Species of Nephropsis Wood-Mason, 1872 (Decapoda: Astacidea: Nephropidae). Journal of Crustacean Biology. 46(2); ruag015. DOI: doi.org/10.1093/jcbiol/ruag015 [10 April 2026 ]

 

[Crustacea • 2026] Merapohra karsticola • On A New Genus and Species of Karst-dwelling Freshwater Crab (Brachyura: Potamidae) from Peninsular Malaysia

 

Merapohra karsticola  

Tan, Ooi & Ng, 2026

 

DOI: doi.org/10.3897/zookeys.1277.181453  

Abstract

Recent explorations of caves in Pahang, central Peninsular Malaysia yielded specimens of an unusual long-legged terrestrial, cave-dwelling crab. Morphological examinations of the specimens collected, in comparison with known species from the region suggests that they belong to a new genus and species, which are described herein. Merapohra karsticola gen. nov. et sp. nov., is differentiated from other potamids by characters of the carapace epigastric and postorbital cristae, ambulatory legs, male thoracic sternum, male pleon, and diagnostic structure of the male first gonopod. The discovery of this new genus and species of cave-dwelling crab highlights the importance and high diversity of karst systems in Peninsular Malaysia, which are imperilled in light of ongoing quarrying and mining activities.

Key words: Cave, karst, limestone, Potamiscinae, taxonomy

Merapohra karsticola gen. nov. et sp. nov., in life.
A. Holotype, male (37.2 × 26.7 mm) (ZRC 2024.0327);
B. Paratype, female (30.0 × 21.4 mm) (ZRC 2024.0328).

(Photo credit: Mr. Ang Yu Pin for the paratype).

Merapohra karsticola gen. nov. et sp. nov.

 Zhi Wan Tan, Qie Ooi, Peter K. L. Ng. 2026. On A New Genus and Species of Karst-dwelling Freshwater Crab (Crustacea, Brachyura, Potamidae) from Peninsular Malaysia. ZooKeys. 1277: 113-136.  DOI: doi.org/10.3897/zookeys.1277.181453 [9 Apr 2026]

[Crustacea • 2026] Caridina zhaoi • A New stygobiont atyid Shrimp (Decapoda: Caridea: Atyidae) from a limestone cave in Guizhou Province, China

 

Caridina zhaoi

Jiang, Zhou & Chen, 2026 

 DOI: doi.org/10.3897/zse.102.182296

Abstract

A new stygobiont species of freshwater shrimp, Caridina zhaoi sp. nov., from a karst cave in Guiyang, Guizhou Province, southwestern China, is described and illustrated. The new species is morphologically distinct from its epigean congeners by a suite of stygobiotic characters, including the degeneration of eyes and absence of body pigmentation. It can be further distinguished from other known Chinese cavernicolous Caridina species by the combination of a relatively long rostrum with a specific rostral formula, the length of the stylocerite, the proportions of various joints of the first and second pereiopods, and the armature of the dactylus of the third and fifth pereiopods. Molecular analysis based on the mitochondrial COI gene reveals a high genetic divergence (14.70%–23.47%) between the new species and other atyids, supporting its validity as a distinct species. This discovery brings the total number of stygobiont Caridina species in China to 10, highlighting the rich but underestimated subterranean biodiversity of the Guizhou karst region.

Key Words: COI, Crustacea, morphology, stygofauna, subterranean biodiversity, taxonomy

A. The entrance of Xiangshui Cave; B. Live specimen of Caridina zhaoi sp. nov..

Caridina zhaoi sp. nov.

 Xuankong Jiang, Jiajun Zhou and Huiming Chen. 2026. Caridina zhaoi sp. nov., A New stygobiont atyid Shrimp (Decapoda, Caridea, Atyidae) from a limestone cave in Guizhou Province, China. Zoosystematics and Evolution. 102(2): 601-609. DOI: doi.org/10.3897/zse.102.182296 [06 Apr 2026]

[Crustacea • 2026] Alpheopsis gorei • A mesophotic alpheid Shrimp (Decapoda: Caridea: Alpheidae) from the western Atlantic

Alpheopsis gorei  Anker, 2026

Papéis Avulsos De Zoologia. 66;  

 revistas.usp.br/PAZ

 Photograph by Sarah Tweedt. 

Abstract

A new mesophotic alpheid shrimp, Alpheopsis gorei sp. nov., is described from several offshore localities in the northern and north-eastern Gulf of Mexico off Texas, Louisiana and western Florida. However, the distribution range of the new species extends to the Atlantic coast of Florida, with a previous record from deep-water reefs off Key Largo, under A. trispinosa Stimpson, 1860. The presently known bathymetric range of A. gorei sp. nov. is 42.1-126.2 m and the species appears to be free-living, mainly among coralline nodules and in crevices of deep coral rubble. The new species is morphologically closest to the eastern Altantic A. africana Holthuis, 1952 and A. azorica Anker, Poddoubtchenko & d’Udekem d’Acoz, 2005, the eastern Pacific A. equidactylus Lockington, 1877, and the Indo-West Pacific A. trispinosa, A. garricki Yaldwyn, 1971 and A. keijii Anker, 2007, differing from each of them by at least two morphological characters.

Keywords: Atlantic Ocean, USA, Gulf of Mexico, Florida, Crustacean, Deep-water shrimp, Alpheidae, ROV, ARMS

Alpheopsis gorei sp. nov., paratype, ov. female, cl 3.5 mm, off Louisiana, USA (USNM 1745065), shrimp alive, dorsal. Photograph by Sarah Tweedt.  

Alpheopsis gorei sp. nov.

Etymology: The new species is named after the decapod taxonomist, marine ecologist and biogeographer, Dr. Richard H. Gore, who first reported it from Florida (Gore, 1981, as A. trispinosus). 

Arthur Anker. 2026. Description of Alpheopsis gorei sp. nov., A mesophotic alpheid Shrimp from the western Atlantic (Decapoda: Caridea). Papéis Avulsos De Zoologia. 66; e202666006. DOI: 10.11606/1807-0205/2026.66.006 [2026-03-03]

  revistas.usp.br/PAZ/article/view/237897